Skip to content

Only consider primary flows in the topological sort #949

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 6 commits into from
Oct 20, 2025
Merged

Only consider primary flows in the topological sort #949

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
3590151
Only consider primary flows in the topological sort
tsmbland Oct 20, 2025
4cbd8eb
Add styling for edges
tsmbland Oct 20, 2025
2916524
Add function for styling edges
tsmbland Oct 20, 2025
6291be5
Use enum for Primary/Secondary flows
tsmbland Oct 20, 2025
1f69ba3
Small touch ups
tsmbland Oct 20, 2025
0a12365
Remove unnecessary clone
tsmbland Oct 20, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 2 additions & 0 deletions docs/user_guide.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -112,6 +112,8 @@ This command will output a graph for each region/year in the simulation, where n
and edges are processes.
Graphs will be saved in [DOT format], which can be visualised locally with [Graphviz], or online
with [Graphviz online].
Dashed lines are used to indicate flows for non-primary outputs of a process (as defined in the
`processes.csv` input file).

[the `muse2 save-graphs` command]: https://energysystemsmodellinglab.github.io/MUSE2/command_line_help.html#muse2-save-graphs
[DOT format]: https://graphviz.org/doc/info/lang.html
Expand Down
80 changes: 58 additions & 22 deletions src/graph.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,8 @@ use itertools::{Itertools, iproduct};
use petgraph::Directed;
use petgraph::algo::toposort;
use petgraph::dot::Dot;
use petgraph::graph::Graph;
use petgraph::graph::{EdgeReference, Graph};
use petgraph::visit::EdgeFiltered;
use std::collections::HashMap;
use std::fmt::Display;
use std::fs::File;
Expand Down Expand Up @@ -48,16 +49,20 @@ impl Display for GraphNode {
#[derive(Eq, PartialEq, Clone, Hash)]
/// An edge in the commodity graph
pub enum GraphEdge {
/// An edge representing a process
Process(ProcessID),
/// An edge representing a primary flow of a process
Primary(ProcessID),
/// An edge representing a secondary (non-primary) flow of a process
Secondary(ProcessID),
/// An edge representing a service demand
Demand,
}

impl Display for GraphEdge {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
GraphEdge::Process(id) => write!(f, "{id}"),
GraphEdge::Primary(process_id) | GraphEdge::Secondary(process_id) => {
write!(f, "{process_id}")
}
GraphEdge::Demand => write!(f, "DEMAND"),
}
}
Expand Down Expand Up @@ -111,6 +116,9 @@ fn create_commodities_graph_for_region_year(
outputs.push(GraphNode::Sink);
}

// Get primary output for the process
let primary_output = &process.primary_output;

// Create edges from all inputs to all outputs
// We also create nodes the first time they are encountered
for (input, output) in iproduct!(inputs, outputs) {
Expand All @@ -120,10 +128,19 @@ fn create_commodities_graph_for_region_year(
let target_node_index = *commodity_to_node_index
.entry(output.clone())
.or_insert_with(|| graph.add_node(output.clone()));
let is_primary = match &output {
GraphNode::Commodity(commodity_id) => primary_output.as_ref() == Some(commodity_id),
_ => false,
};

graph.add_edge(
source_node_index,
target_node_index,
GraphEdge::Process(process.id.clone()),
if is_primary {
GraphEdge::Primary(process.id.clone())
} else {
GraphEdge::Secondary(process.id.clone())
},
);
}
}
Expand Down Expand Up @@ -157,13 +174,13 @@ fn prepare_commodities_graph_for_validation(
let key = (region_id.clone(), year);
filtered_graph.retain_edges(|graph, edge_idx| {
// Get the process for the edge
let GraphEdge::Process(process_id) = graph.edge_weight(edge_idx).unwrap() else {
panic!("Demand edges should not be present in the base graph");
let process_id = match graph.edge_weight(edge_idx).unwrap() {
GraphEdge::Primary(process_id) | GraphEdge::Secondary(process_id) => process_id,
GraphEdge::Demand => panic!("Demand edges should not be present in the base graph"),
};
let process = &processes[process_id];

// Check if the process has availability > 0 in any time slice in the selection

time_slice_selection
.iter(time_slice_info)
.any(|(time_slice, _)| {
Expand Down Expand Up @@ -242,7 +259,7 @@ fn validate_commodities_graph(
// Match validation rules to commodity type
match commodity.kind {
CommodityType::ServiceDemand => {
// Cannot have outgoing `Process` (non-`Demand`) edges
// Cannot have outgoing `Primary`/`Secondary` (non-`Demand`) edges
let has_non_demand_outgoing = graph
.edges_directed(node_idx, petgraph::Direction::Outgoing)
.any(|edge| edge.weight() != &GraphEdge::Demand);
Expand Down Expand Up @@ -289,8 +306,12 @@ fn topo_sort_commodities(
graph: &CommoditiesGraph,
commodities: &CommodityMap,
) -> Result<Vec<CommodityID>> {
// We only consider primary edges
let primary_graph =
EdgeFiltered::from_fn(graph, |edge| matches!(edge.weight(), GraphEdge::Primary(_)));

// Perform a topological sort on the graph
let order = toposort(graph, None).map_err(|cycle| {
let order = toposort(&primary_graph, None).map_err(|cycle| {
let cycle_commodity = graph.node_weight(cycle.node_id()).unwrap().clone();
anyhow!("Cycle detected in commodity graph for commodity {cycle_commodity}")
})?;
Expand Down Expand Up @@ -413,6 +434,16 @@ pub fn validate_commodity_graphs_for_model(
Ok(commodity_order)
}

/// Gets custom DOT attributes for edges in a commodity graph
fn get_edge_attributes(_: &CommoditiesGraph, edge_ref: EdgeReference<GraphEdge>) -> String {
match edge_ref.weight() {
// Use dashed lines for secondary flows
GraphEdge::Secondary(_) => "style=dashed".to_string(),
// Other edges use default attributes
_ => String::new(),
}
}

/// Saves commodity graphs to file
///
/// The graphs are saved as DOT files to the specified output path
Expand All @@ -421,7 +452,12 @@ pub fn save_commodity_graphs_for_model(
output_path: &Path,
) -> Result<()> {
for ((region_id, year), graph) in commodity_graphs {
let dot = Dot::new(&graph);
let dot = Dot::with_attr_getters(
graph,
&[],
&get_edge_attributes, // Custom attributes for edges
&|_, _| String::new(), // Use default attributes for nodes
);
let mut file = File::create(output_path.join(format!("{region_id}_{year}.dot")))?;
write!(file, "{dot}")?;
}
Expand All @@ -447,8 +483,8 @@ mod tests {
let node_c = graph.add_node(GraphNode::Commodity("C".into()));

// Add edges: A -> B -> C
graph.add_edge(node_a, node_b, GraphEdge::Process("process1".into()));
graph.add_edge(node_b, node_c, GraphEdge::Process("process2".into()));
graph.add_edge(node_a, node_b, GraphEdge::Primary("process1".into()));
graph.add_edge(node_b, node_c, GraphEdge::Primary("process2".into()));

// Create commodities map using fixtures
let mut commodities = CommodityMap::new();
Expand All @@ -474,8 +510,8 @@ mod tests {
let node_b = graph.add_node(GraphNode::Commodity("B".into()));

// Add edges creating a cycle: A -> B -> A
graph.add_edge(node_a, node_b, GraphEdge::Process("process1".into()));
graph.add_edge(node_b, node_a, GraphEdge::Process("process2".into()));
graph.add_edge(node_a, node_b, GraphEdge::Primary("process1".into()));
graph.add_edge(node_b, node_a, GraphEdge::Primary("process2".into()));

// Create commodities map using fixtures
let mut commodities = CommodityMap::new();
Expand Down Expand Up @@ -508,8 +544,8 @@ mod tests {
let node_b = graph.add_node(GraphNode::Commodity("B".into()));
let node_c = graph.add_node(GraphNode::Commodity("C".into()));
let node_d = graph.add_node(GraphNode::Demand);
graph.add_edge(node_a, node_b, GraphEdge::Process("process1".into()));
graph.add_edge(node_b, node_c, GraphEdge::Process("process2".into()));
graph.add_edge(node_a, node_b, GraphEdge::Primary("process1".into()));
graph.add_edge(node_b, node_c, GraphEdge::Primary("process2".into()));
graph.add_edge(node_c, node_d, GraphEdge::Demand);

// Validate the graph at DayNight level
Expand All @@ -535,8 +571,8 @@ mod tests {
let node_c = graph.add_node(GraphNode::Commodity("C".into()));
let node_a = graph.add_node(GraphNode::Commodity("A".into()));
let node_b = graph.add_node(GraphNode::Commodity("B".into()));
graph.add_edge(node_c, node_a, GraphEdge::Process("process1".into()));
graph.add_edge(node_a, node_b, GraphEdge::Process("process2".into()));
graph.add_edge(node_c, node_a, GraphEdge::Primary("process1".into()));
graph.add_edge(node_a, node_b, GraphEdge::Primary("process2".into()));

// Validate the graph at DayNight level
let result = validate_commodities_graph(&graph, &commodities, TimeSliceLevel::DayNight);
Expand Down Expand Up @@ -573,7 +609,7 @@ mod tests {
// Build invalid graph: B(SED) -> A(SED)
let node_a = graph.add_node(GraphNode::Commodity("A".into()));
let node_b = graph.add_node(GraphNode::Commodity("B".into()));
graph.add_edge(node_b, node_a, GraphEdge::Process("process1".into()));
graph.add_edge(node_b, node_a, GraphEdge::Primary("process1".into()));

// Validate the graph at DayNight level
let result = validate_commodities_graph(&graph, &commodities, TimeSliceLevel::DayNight);
Expand All @@ -600,8 +636,8 @@ mod tests {
let node_a = graph.add_node(GraphNode::Commodity("A".into()));
let node_b = graph.add_node(GraphNode::Commodity("B".into()));
let node_c = graph.add_node(GraphNode::Commodity("C".into()));
graph.add_edge(node_b, node_a, GraphEdge::Process("process1".into()));
graph.add_edge(node_a, node_c, GraphEdge::Process("process2".into()));
graph.add_edge(node_b, node_a, GraphEdge::Primary("process1".into()));
graph.add_edge(node_a, node_c, GraphEdge::Primary("process2".into()));

// Validate the graph at DayNight level
let result = validate_commodities_graph(&graph, &commodities, TimeSliceLevel::DayNight);
Expand Down